Hitachi RAC-25YH4, Service Manual, Page: 86 / 121

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SERVICE CALL Q & A
Model RAS-25YH4 / RAC-25YH4
RAS-35YH4 / RAC-35YH4
COOLING MODE
The compressor has
Fan speed is not switched over
during dehumidifying operation.
Cool air comes from the unit during
dehumidifying operation.
Fans speed is normally set to LOW during
dehumidifying operation.
To have an operation with high dehumidifying
effect, the unit operates at low fan speed.
As a result, cool air comes from the unit.
This phenomenon is not a fault.
stopped suddenly during
cooling operation.
The circulation stops
occasionally during
Heating mode.
When the fan speed is set
at HIGH or MED, the flow
is actually Weak.
Heating operation stops
When “Auto fan” mode is set,
the indoor fan speed changes
from HIGH through MED to
LOW.
while the temperature is
preset at "30".
Check if the indoor heat
exchanger is frosted.
Wait for 3-4 minutes
until it is defrosted. If the air conditioner operates
in cooling mode when it is
cold, the evaporator may get
frosted.
It occurs during defrost-
ing. Wait for 5-10
minutes until the
condenser is defrosted.
At the beginning of heating,
the fan speed remains
LOW for 30 seconds. If
HIGH is selected, it
switches to LOW and again
to MED after additional 30
seconds.
If temperature is high in
This is not an error.
The anti cool air function
shows this phenomenon.
In the fan “Auto” mode, the unit
detects the heat exchange
temperature. When the
temperature becomes low,
the fan speed changes from
HIGH, through MED to LOW.
the outdoor, heating
operation may stop to
protect internal devices.
DEHUMIDIFYING MODE
HEATING MODE
Q1 A1
Q2
A2
Q3
A3
Q4 A4
Q5 A5
Q6 A6
Q7 A7
RAS_25_35_AW_055-086 2003.12.31, 10:59 AM 84